The widespread distribution in the environment of cyclopenteno(cd) pyrene (CPEP) and its carcinogenic activity in preliminary studies indicate the need for thorough investigation of the biological properties of this hydrocarbon. This proposal is concerned with the synthesis, carcinogenicity, mutagenicity, metabolism and binding studies of CPEP. Its 3,4 dihydro derivative cyclopentano(cd)pyrene (CPAP), a constituent of coal tar pitch, will also be an integral part of this study. A simple and efficient synthesis of CPEP is proposed, and will also be applicable to preparation of a 14C analog. CPAP and some of the major potential metabolites will be synthesized from CPEP. The carcinogenic effect of CPEP will be proven definitively by repeated application and initiation-promotion in mouse skin. The carcinogenicity of CPAP will also be tested. The biological effect of the two hydrocarbons will be compared to that of the potential carcinogenic metabolite of CPEP, CPEP-3,4-oxide and of the environmental carcinogen benzo(a)pyrene (BP). In addition, the carcinogenic effect of CPEP and BP will be investigated at relative ratios of the hydrocarbons in various carbon blacks. The metabolism of (14C)CPEP and (14C)CPAP will be studied with mouse skin homogenates and microsomes of induced and uninduced mice. Mutagenicity of synthesized and identified metabolites of CPEP and CPAP will be tested in Salmonella typhimurium. The comparative binding level of 14C-labeled CPEP, CPAP and BP to mouse skin DNA will also be an integral part of our studies. Furthermore, analysis and comparison of nucleic acid base-CPEP adducts will be conducted. The adducts will be obtained from a. DNA incubated with CPEP-3,4 oxide and hydrolyzed to monomers, b. DNA incubated with CPEP and liver microsomes c. hydrolyzed DNA from mouse skin treated with CPEP. The combined studies of metabolism, mutagenicity, carcinogenicity and binding of CPEP should cast light on its mechanism of activation. These collected data, along with epidemiological and analytical data, will allow a more precise assessment of the environmental and occupational health hazard of CPEP.